The invention relates generally to device wherein charged particles are attracted to and deposited on one or more electrodes. More particularly, the invention relates to electrofilters or electrostatic precipitators. Of special interest are the electrodes used in such devices.
In electrostatic precipitators, a path is provided for the passage of a gas such as air. Collector electrodes, that is, electrodes to which charged particles are attracted and on which they deposit, are located in this path or immediately adjacent thereto so as to bound the same. An electrostatic field is set up between a collector electrode and a counterelectrode or discharge electrode, and the influence of this field causes ionized impurity particles to be attracted to the collector electrode so that they are separated from the other particles of the gas. Normally, the counterelectrode or discharge electrode also defines a collector electrode and the particular collector electrode to which the ionized impurity particles are attracted will depend upon the sign of the charge carried by the impurity particles. If necessary, an ionization region may be provided upstream of the region where separation of the impurity particles occurs.
Since, by virtue of their function, the collector electrodes become rapidly contaminated, care has heretofore been taken to insure that they could be easily cleaned. The collector electrodes were thus made of metal and provided with smooth surfaces and were installed in such a manner that they were easily accessible. Moreover, in order to avoid the cleaning operation entirely, it has also become known to replace these metal electrodes with readily exchangeable disposable elements which are composed of an inexpensive material such as metallized cardboard, conductive synthetic resin or the like. Insofar as the form and surface characteristics of the known disposable electrodes are concerned, these are the same as those of the metal electrodes. However, it has been found that the form and surface characteristics of the known electrodes leave something to be desired as regards the collecting power of the electrodes, that is, the ability of the electrodes to attract and retain charged particles.